A TECHNIQUE FOR IMPROVING QUALITY OF POSITION EMISSION TOMOGRAPHY (PET) IMAGES USING CRADLE DEFLECTION DATA
Publication Date: 2016-Mar-17
The IP.com Prior Art Database
A technique for cradle deflection compensation in positron emission tomography (PET) image reconstruction is disclosed. The technique enhances quality of the reconstructed PET image by capturing and integrating patient position information in real time during a PET-CT scan. The patient position information includes cradle position in z direction and also the cradle deflection angle in y direction.
The present disclosure relates generally to position emission tomography (PET) image reconstruction and more particularly to a technique for cradle deflection compensation in PET image reconstruction.
A patient table provides support to a patient during a positron emission tomography (PET) and computed tomography (CT) image acquisition. Generally, the patient supported on the table or cradle is advanced through the PET and CT bores for specified lengths, speeds, and position repeatedly at working loads of up to 500 lbs. The CT or PET system controls the table longitudinal motions during scanning, and the operator can move all table axes manually by means of the gantry control panel buttons. As depicted in Figure 1, based on patient load, the table deflects or sags when the table is fully extended in the PET axial field of view (FOV).
The sag in table, results in a mismatch between CT images and PET images. This mismatch often causes an alignment error and inaccurate attenuation correction in PET reconstruction and inaccurate PET-CT image registration. The deflection in the table also results in an error in stitching of two frames/beds images. Amount of sag is a function of patient weight. Also, a bigger PET axial FOV has a higher alignment error due to the sag.
One conventional techniques use interpolation for correction of the alignment error thereby providing an approximate solution. Another conventional technique attempts correction by measuring the cradle deflection using an additional CT scan. Another conventional technique proposes using a radioactive marker during PET-CT scans to correct for cradle deflection. However, having a radioactive source during PET acquisition is not recommended and an additional CT scan adds radiation exposure. Another conventional technique uses mechanical apparatus including pivot, pulleys and springs for measuring the snag in the table. Other conventional techniques used for correcting include a dual system for two separate imaging configurations, acquiring separate tomographic images of the table with and without the patient, and a data acquisition subsystem for receiving the deflection information from the measurement subsystem and PET measurement data corresponding to a plurality of coincidence events from the PET scanner. However, these conventional techniques do not provide dynamic data in real-time. Cradle deflection for every patient is different depending on the size, weight, location and orientation and a dynamic measurement of real-time deflection trajectory of the table is required for optimal image registration.
It would be desirable to have an improved technique for cradle deflection compensation in PET image reconstruction.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 depicts deflection in table based on patient load.
Figure 2 depicts a flex sensor strip mounted on the ...